The present invention relates generally to a bone elimination apparatus, and more specifically, to a means for regulating the discharge of bones and other hard materials from a bone elimination apparatus.
In the food processing industry animal carcasses or remnants are used to produce ground food material. After choice and select portions of the animal are removed from the carcasses, some useable portions of food remain on the carcasses. This useable material may be recovered from the carcasses by subjecting the carcasses to a grinding process. In such processes, the animal carcasses are inserted into a grinding apparatus where the useable food material is processed into a ground form, while the remaining bone and hard tissues are separated and discharged from the grinding apparatus to waste.
Bone elimination devices are well known in the food processing industry. For the most part, these devices are used in association with a grinding apparatus of the type having a tubular grinding chamber with a rotating compression screw or auger extending within the grinding chamber. Food parts, such as carcasses or remnants, are placed into the chamber where the auger contacts and drives the food material through the tube, forming a food material mass in the grinding chamber. The auger may include a series of grinding blades which cut the useable material from the carcasses and may also press it against a perforated portion of the grinding chamber. The auger compresses the food material against the perforations and forces the useable, ground food material out of the grinding chamber through the perforations while retaining the bones and connective tissues in the grinding chamber.
The bones and hard tissue are heavier than the useable soft material of the carcasses so that during the grinding process, this heavier material tends to collect along the auger shaft where it is pushed down the length of the grinding chamber to the end of the grinding chamber. This unusable material is typically discharged through a tube extending out of the meat grinding chamber to a waste collection point. Examples of bone removal equipment having a structure as noted above are fully described in U.S. Pat. Nos. 4,536,920 issued Aug. 27, 1985 and Re. 31,631, issued Jul. 17, 1984.
The equipment described in these two patents utilize an orifice of decreasing size which collects the bones and hard material for discharge and expels them through a discharge opening. Depending on the type of food material being processed, some useable food material may remain on the carcasses or remnants. Other patents describe devices which are suitable for recovering useable food material which still may be attached on the unusable hard portions of the carcasses after a first grinding. Such an apparatus is described in U.S. Pat. No. 5,251,829, issued Oct. 12, 1993 to Weiler and Company of Whitewater, Wis. This patent describes a bone collector assembly in which an additional, or secondary, grinding chamber is located downstream of the primary grinding chamber. This secondary grinding chamber has an additional auger and knife assembly which grinds the hard material discharged from the first grinding chamber a second time, thereby increasing the yield of the useable food material from carcasses.
In using an apparatus of the type described in the above-mentioned '829 patent, it has come to be appreciated that occasionally relatively large amounts of food material are discharged from the grinder apparatus in sporadic spurts as a result of the overall backpressure within the system. When food material is discharged from such a grinding apparatus in large spurts, the backpressure of the system is reduced, and useable food material may be easily ejected out of the grinder along with the unusable material. When large amounts of useable material are discharged in this manner, some food processors may reintroduce the expelled material back into the grinding apparatus for regrinding in an attempt to recover additional useable material. When this reintroduction occurs, the likelihood is increased that some of the hard unusable portions of the food material may be ground into the useable food material, leading to an inferior quality of the ultimate processed food product.
The present invention is therefore directed to a solution to this problem by providing a means to increase the backpressure of the grinding system which regulates the discharge of bones and hard materials from the grinder, thereby substantially eliminating the need to regrind discharged material and reducing the likelihood of reintroducing bone and foreign objects into the processed food material.
In accordance with the present invention, a discharge valve means is provided within the discharge tube of a food grinder which provides control over the flow and backpressure of the grinding apparatus. The valve means is contained within a housing adapted for connection to the discharge opening of a food grinding apparatus. The valve means includes a valve element slidably mounted therein between inlet and outlet openings of the housing. Movement of the valve element occurs along the longitudinal axis of the housing. The valve element includes a valve head or plug for sealing the inlet of the control housing which consequently seals the discharge of the grinding apparatus. The walls of the inlet opening of the control housing serve as the valve seat and cooperate with a multi-surfaced portion of the valve head to regulate a precise flow rate of discharge out of the system so as to remove only rejectable material from the grinder product flow stream.
The multiple surfaces of the valve head serve to increase the overall surface area of the valve head (as compared to a valve element having a constant planar pressure surface profile) in contact with the grinder product flow stream. In a preferred profile, the valve may include a circular groove which extends lengthwise within the valve head at an angle from its axis to define a variable discharge passage in the valve head, such that as the system pressure increases, the valve opening incrementally increases to reduce back pressure on the system so that substantially only rejectable food material is removed from the grinder product flow stream.
Accordingly, it is an object of the present invention to provide a means for regulating the discharge of bones and other hard material from a food material grinder.
It is another object of the present invention to provide a means for increasing the backpressure of a food material grinding apparatus having a bone discharge device which incorporates a flow control means into the bone discharge line of the grinding apparatus which regulates the amount of unusable material discharged from the grinding apparatus, which discharge is regulated solely by the flow of unusable material exiting from the grinding apparatus and not by any external regulation means.
It is still another object of the present invention to provide a means for providing a controlled backpressure on a discharge line of a food material grinding apparatus and thereby regulating the discharge of bones and unusable food material out of the grinding apparatus, wherein the means includes a discharge flow control valve disposed within a bone discharge line, the valve having a valve element which contains a groove of variable size, the size of the groove depending upon the movement of the valve element within the housing in response to the grinding apparatus backpressure, which groove is in contact with the grinding apparatus product flow stream.
Yet another object of the present invention is to provide a bone discharge regulating device for use on a food material grinder having a bone elimination and discharge component, wherein the device is mounted in a discharge line of the bone elimination and discharge component and includes a valve element having a multiple surface profile in contact with the product flow stream, the valve element including a reciprocatable plunger element disposed in the discharge line, the plunger element having a longitudinal groove extending therein, the groove presenting a valve opening which has a specific size at an open position of the valve and which steadily decreases as the valve closes, thereby providing a variable opening within the plunger element which permits bone material to pass through the discharge line through the plunger element groove.
Another object of the present invention is to provide a means for controlling the flow of waste material out of a food grinding apparatus which substantially reduces the overall amount of material discharged to waste from the grinding apparatus while removing substantially all of the bones, hard material and foreign objects from the food material being processed.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.